Sexual behaviour after antiretroviral therapy initiation in female sex workers and HIV-positive patients from the general population,Cotonou, Benin

From September 2008 to December 2011, we enrolled and followed-up 247 HIV-negative, 88 untreated and 32 treated HIV-positive female sex workers (FSWs), as well as 238 untreated and 115 treated HIV-positive patients from the general population (GP) of Cotonou, Benin. We wanted to assess the effect of antiretroviral therapy (ART) on sexual risk-taking in FSWs and patients from the GP. We used multivariate log binomial regression models for repeated measures to compare risky behaviours reported during pre-ART and post-ART visits and we performed linear time-trend analyses to assess changes in condom use in all five groups. At 58.8% of pre-ART and 45.3% of post-ART visits (adjusted p-value=0.293), treated FSWs have reported ≥16 clients during the last week of work. Inconsistent condom use with clients over the same period decreased by more than 50% (from 20.7 to 10.0%, adjusted p-value=0.082). In treated patients from the GP, inconsistent condom use with regular partners during the last four months was reported at 52.8% of pre-ART and 53.5% of post-ART visits (p=0.778). Reported casual sex was stable (36.8% versus 38.7%, adjusted p-value=0.924). In linear time-trend analyses, there was a significant downward trend in inconsistent condom use at the early stage of the study and stability thereafter in all HIV-negative and HIV-positive FSWs. There was no negative alteration in sexual behaviour following ART initiation either inpatients from the GP or in FSWs. The results underscore the key role of concomitant sexual risk-reduction strategies.     

IgE and IgG4 antibody responses to Aedes saliva in African children

Aedes mosquitoes are the major vectors of (re)-emerging infections including arboviruses (dengue, Chikungunya, yellow fever) in developing countries. Moreover, the emergence of Aedes-borne diseases in the developed world is currently a source of concern. Evaluation of human immune responses to Aedes bites could be a useful immuno-epidemiological tool for evaluating exposure to Aedes-borne diseases and thus predicting the risk of such emerging diseases. Specific IgE and IgG4 antibody (Ab) responses to Aedes aegypti saliva were evaluated in young Senegalese children living in an area of exposure to the Aedes vector. Specific IgE and IgG4 responses increased during rainy season of high exposure to Aedes bites. In addition, the evolution of anti-saliva isotype levels during the rainy season presented spatial heterogeneity between the studied villages. These preliminaries results support the potential approach of using anti-saliva Ab responses for evaluating exposure to Aedes vectors and risks of emerging arbovirus infections.     

Evaluation of HIV-1 p24 antigenemia and level of CD8+CD38+ T cells as surrogate markers of HIV-1 RNA viral load in HIV-1-infected patients in Dakar, Senegal

Alternative, affordable, and simple assays to monitor antiretroviral therapy (ART) in resource-poor settings are needed. We have evaluated and compared a heat-denatured (HD) HIV p24 amplified enzyme-linked immunosorbent assay from Perkin-Elmer and CD38CD8 T-cell levels, determined by flow cytometry, for their capacity to predict viral load (VL) in HIV-1-infected patients from Senegal. Median fluorescence intensity (MFI) of CD38 expression on memory (CD45RO) CD8 T cells correlated better with RNA VL than HD p24 antigenemia (R = 0.576, P < 0.0001 vs R = 0.548, P < 0.0001). MFI of CD38 expression on memory CD8 T cells could predict detectable RNA VL (VL = 2.6 log10) with a sensitivity of 87% and a specificity of 74%. A comparable sensitivity (89%) could be reached for HD p24 assay, but only to predict RNA VL of more than 5 logs, which might lead to unacceptable delays in clinical decision making. The clinical use of the HD p24 assay to monitor ART in Senegal would require more comparative data about the kinetics of p24 antigen and HIV RNA in peripheral blood as well as further evaluation regarding its sensitivity toward subtype A and CRF02. MFI of CD38 expression on memory CD8 T cells appeared to be a better alternative to monitor ART in HIV-infected patients from Senegal.     

Survival of comatose stroke victims in a neurological department in Dakar

BACKGROUND: In Dakar, stroke is the most frequent neurological disease with the highest mortality. Victims may present in a critical state of coma. The objective of this study was to evaluate survival among comatose stroke patients in Dakar, Senegal. METHODS: This was a longitudinal prospective study from April 2006 to July 2007 conducted in the Neurological Intensive Care Unit (NICU) of Fann University Teaching Hospital in Senegal. Were included in the study, all stroke patients confirmed by CT scan with a Glasgow coma score less than or equal to 8/15. Patients with subarachnoid hemorrhage were excluded. RESULTS: A total of 105 patients were evaluated with 54 cases of ischemic stroke among them. The mean age was 61.87+/-14.16 years. The mean duration of hospital stay in the NICU was 10.82+/-11 days with an estimated mortality of 82.9%; the three-month survival was 9.52%. The median overall survival was 7+/-1 days (CI(95%): 5-9). CONCLUSION: Comatose stroke patients have a poor prognosis, emphasizing the crucial importance of primary prevention.     

Antimalarial activity of Sida acuta Burm. f. (Malvaceae) and Pterocarpus erinaceus Poir. (Fabaceae)

Among strategies to combat malaria, the search for new antimalarial drugs appears to be a priority. Sheering for new antimalarial activities, four plants of the traditional medicine of Burkina Faso: Combretum micranthum, Khaya senegalensis, Pterocarpus erinaceus and Sida acuta, were tested in vitro on fresh clinical isolates of Plasmodium falciparum. The screening showed that Sida acuta has a significant activity (IC50 < 5 microg/ml), and Pterocarpus erinaceus has a moderate activity (5 microg/ml < IC50 < 50 microg/ml). Further chemical screening showed that the activity of the most active plant, Sida acuta, was related to its alkaloid contents.     

Relation between HIV-2 proviral load and CD4+ lymphocyte count differs in monotypic and dual HIV infections

OBJECTIVE: To explore and compare the relations between proviral DNA load and CD4+ lymphocyte counts in both HIV-2 monotypic and HIV dual infection. STUDY DESIGN/METHODS: In Dakar, Senegal, where the HIV-1 and HIV-2 epidemics overlap, serum and peripheral blood mononuclear cell (PBMC) DNA samples were collected from registered female sex workers and hospitalized patients. Sera were evaluated for reactivity to antigens of HIV-1 and HIV-2 by immunoblot; dual reactivity was confirmed with recombinant envelope peptides for HIV-1 and HIV-2. These samples were then subjected to HIV-1 and HIV-2 proviral DNA polymerase chain reaction (PCR). To evaluate the HIV-2 cellular proviral DNA loads, a quantitative competitive PCR (QC-PCR) was developed using nested primers to amplify the gag region of HIV-2. This assay used an internal competitor generated by inserting 25 bp in the first-round PCR target sequence. T-lymphocyte subset counts were estimated by flow cytometry for both HIV-2 monotypic and dually infected persons. RESULTS: 35 HIV-2-infected and 33 dually seroreactive samples were evaluated in this study. The CD4+ lymphocyte counts were similar in both groups, with mean values of 449 +/- 390 cells/mm3 for the HIV-2 monotypic infected persons and 476 +/- 308 cells/mm3 among the dually infected persons. However, the median proviral loads differed significantly, with those in the HIV-2 group ranging from 63.2 to 669.8 copies/10(5) CD4+ cells and demonstrating an inverse correlation with CD4+ lymphocyte count. The HIV dually infected persons showed less variation in viral load, ranging from 9.9 to 43.3 copies/10(5) CD4+ cells. Among the HIV dually infected persons, low HIV-2 proviral load was correlated with low CD4+ lymphocyte counts. CONCLUSIONS: The HIV-2 proviral loads in HIV dually infected persons were significantly lower than those in HIV-2 monotypically infected individuals (P < .0001), despite comparable CD4+ lymphocyte counts. These results suggest that different HIV-2 proviral dynamics prevail in HIV dual infection.     

Development and evaluation of a DNA enzyme immunoassay method for env genotyping of subtypes A through G of human immunodeficiency virus type 1 group M, with discrimination of the circulating recombinant forms CRF01_AE and CRF02_AG

The tools currently available for genetic subtyping of human immunodeficiency virus type 1 are laborious or can be used only for the analysis of a limited number of samples and/or subtypes. We developed and evaluated a molecular biology-based method using subtype-specific oligonucleotide probes for env genotyping of subtypes A through G, CRF01_AE, and CRF02_AG. DNA enzyme immunoassay (DEIA) genotyping is based on nested PCR amplification of the 5' end of the env gene (proviral DNA), followed by subtype-specific hybridization and immunoenzymatic detection on microplates. DEIA genotyping was validated with a large number of samples (n = 128) collected in Europe (France; n = 47), West-Central Africa (Cameroon; n = 36), and West Africa (Senegal; n = 45). Three different formats, depending on the distribution of subtypes in the three countries, were developed. The results were compared with those obtained by sequencing of the V3-V5 region and phylogenetic analysis or an env heteroduplex mobility assay. Additional sequencing and phylogenetic analyses of the DEIA region (the first codon of the env coding sequence to the middle of conserved region C1 of gp120) were performed to investigate the reasons for discrepancies. Intense and highly specific reactions between the oligonucleotide probes and the corresponding samples were observed. Overall, correct identification was achieved for 107 of 128 samples (83.6%). One sample was not amplified, 10 (8%) were nontypeable (NT), and 10 (8%) were misidentified. Six of the 10 discordant samples were further investigated by phylogenetic analysis, which indicated that these samples corresponded to recombinants involving the env 5' end and the V3 and V5 regions of the two parental clades. Sequencing of NT samples showed numerous differences between sample and probe sequences, resulting in a lack of hybridization, and revealed the limitations of the selected probes in terms of specificity and sensitivity. We demonstrated the feasibility of DEIA genotyping: six subtypes plus the two most prevalent circulating recombinant forms were discriminated by using the 5' end of the env gene. This method can be adapted to the local situation by including only probes that correspond to the prevalent strains.     

Most env and gag subtype A HIV-1 viruses circulating in West and West Central Africa are similar to the prototype AG recombinant virus IBNG

The genetic subtype was identified in gag and env of 219 HIV-1-positive samples collected in different African countries, 44 from Senegal, 55 from Cameroon, 82 from Gabon, and 38 from Djibouti. In total, 20 (9.1%) samples had discordant subtypes between gag and env, 6 of 44 (13.9%) in Senegal, 4 of 55 (7.2%) in Cameroon, 1 of 38 (2.6%) in Djibouti, and 10 of 82 (12.1%) in Gabon. Subtypes A and G were predominantly involved in the recombination events. Phylogenetic tree analysis of gag showed that an important number of the A sequences form a distinct subcluster with the AG-IBNG prototype strain (a complex A/G mosaic virus): 27 of 32 (84.3%) in Senegal, 12 of 17 (70.6%) in Nigeria, 24 of 39 (61.5%) in Cameroon, and 38 of 70 (54.3%) in Gabon. Full-length genome analysis of 3 and additional sequences in pol for 10 such strains confirmed that they have a similar complex A/G mosaic genomic structure. These data suggest that in West Africa, most probably between 60% and 84% of the subtype A viruses are recombinant AG-IBNG viruses. This finding has potential implications on future vaccine, diagnostic, and treatment strategies. The actual and future role of these viruses in the global pandemic must be monitored in all new molecular epidemiologic studies, a discrimination between subtype A and AG-IBNG-like viruses is necessary.     

High SARS-CoV-2 Seroprevalence among Healthcare Workers in Bamako,Mali

In Mali, a country in West Africa, cumulative confirmed COVID-19 cases and deaths among healthcare workers (HCWs) remain enigmatically low, despite a series of waves, circulation of SARS-CoV-2 variants, the country’s weak healthcare system, and a general lack of adherence to public health mitigation measures. The goal of the study was to determine whether exposure is important by assessing the seroprevalence of anti-SARS-CoV-2 IgG antibodies in HCWs. The study was conducted between November 2020 and June 2021. HCWs in the major hospitals where COVID-19 cases were being cared for in the capital city, Bamako, Mali, were recruited. During the study period, vaccinations were not yet available. The ELISA of the IgG against the spike protein was optimized and quantitatively measured. A total of 240 HCWs were enrolled in the study, of which seropositivity was observed in 147 cases (61.8%). A continuous increase in the seropositivity was observed, over time, during the study period, from 50% at the beginning to 70% at the end of the study. HCWs who provided direct care to COVID-19 patients and were potentially highly exposed did not have the highest seropositivity rate. Vulnerable HCWs with comorbidities such as obesity, diabetes, and asthma had even higher seropositivity rates at 77.8%, 75.0%, and 66.7%, respectively. Overall, HCWs had high SARS-CoV-2 seroprevalence, likely reflecting a “herd” immunity level, which could be protective at some degrees. These data suggest that the low number of cases and deaths among HCWs in Mali is not due to a lack of occupational exposure to the virus but rather related to other factors that need to be investigated.